Currently there is no support for cross platform multiplayer in ESO and there likely never will be. This means you cannot play with players from Xbox Live while playing in the Playstation Network. Sony are annoyingly restrictive when it comes to cross platform gaming and will not allow it under any circumstances. Just look at the Rocket League disaster. Microsoft are open to it however and if it is ever going to happen for this game it will be between PC and Xbox One. As of right now though, there is no cross platform multiplayer.